Window assemblies for enclosures

ABSTRACT

Frames are disclosed for mounting windows within the walls of enclosures for isolating or sealing substances such as radioactive or other hazardous substances from the surrounding environment. In a first embodiment of the present invention, a window assembly includes a two-piece frame that is welded into the wall of an enclosure. In a second embodiment of the present invention, a window assembly includes a three-piece frame that is clamped to the wall of an enclosure. The frame assemblies may also be used to mount structures other than windows to enclosure walls, such as ducts or pipes intended for passing power, gas, vacuum, or other utilities into the interior of an enclosure.

BACKGROUND OF THE INVENTION

Field of the Invention: The present invention relates to mountingstructures to the walls of enclosures used for isolating or sealingsubstances within the enclosures from the surrounding environment. Moreparticularly, the present invention relates to window assemblies forsuch enclosures that provide improved sealing capabilities andfacilitate installation and removal of windows thereof.

State of the Art: It is often necessary to work with or handle hazardoussubstances that are associated with many of today's industrialprocesses. Waste items contaminated with radiation, for example, mayrequire sorting into separate categories before being disposed of. Themanufacture of medical products may also require risk associatedhandling procedures, such as in making radiopharmaceuticals used incancer treatments or working with biologically active compounds. Whenworking with these substances, it is essential to isolate them fromoperating personnel to protect them from harmful exposure. To this end,enclosures are used that typically comprise rigid-walled containershaving access portals for insertion, removal and manipulation of thehazardous substances, as well as windows to allow observation ofconditions within the container. Enclosures sizes may range fromroom-sized containers intended for holding and processing largequantities of material, down to small containers called “glove boxes”that have glove ports sealed with gloves for individually handling smallquantities of a substance.

To prevent the spread of contamination, the access portals and windowsof an enclosure are sealed in a leak-tight fashion. This is especiallyimportant in situations where there is a pressure differential betweenthe interior of the enclosure and the surrounding environment, as whensubstances must be processed in a vacuum or at low pressure. In the caseof radioactive substances, it is also necessary to form or line theenclosure walls, access portal covers and windows with shielding thatinhibits radiation from escaping from the enclosure. Such radiationshielded enclosures, sometimes referred to as “hot cells,” are commonlyformed with walls and access portal covers comprising stainless steellined with lead and windows impregnated with lead or otherradiation-absorbing materials.

In response to the above described structural requirements, variousapproaches have been developed for mounting and sealing windows withinthe walls of enclosures for containing hazardous substances. One widelyused approach is a window assembly called a “zipper window.” FIGS. 1Aand 1B show a glove box 2 constructed with a zipper window assembly. Asseen in FIG. 1A, glove box 2 includes top, bottom, and side walls 4formed from a material such as plates of stainless steel. Stainlesssteel is desirable for forming walls 4 because it is resistant tocorrosion or other reactive effects that may be associated withsubstances contained within glove box 2. Stainless steel also has asmooth surface finish that is easy to clean, which is important toprevent residual contaminants from building-up within glove box 2. Gloveports 6 are provided for accessing the interior of glove box 2, and awindow 8 is included to allow observation of interior conditions.Various sealed access ports (not shown) may also be included forinserting and removing substances or for passing power, gas and vacuumlines, or other utilities, into the interior of glove box 2.

FIG. 1B is an enlarged sectional side view of a portion of the glove boxin FIG. 1A taken along line X-X showing the zipper window assembly forholding and sealing window 8 in place. A gasket 10 of elastomericmaterial seats window 8 in the window aperture of glove box wall 4.Gasket 10 includes a first U-shaped channel 12 that surrounds the edgesof the aperture in wall 4 and an opposing, second U-shaped channel 14that surrounds the edges of window 8. A wedge member 16 is inserted intoa slot 18 in the side of gasket 10, to compress gasket 10 and seal themedial section of gasket 10 between channels 12 and 14 against theperipheries of wall 4 and window 8. A stainless steel frame 20 may alsobe attached over the interface between wall 4 and window 8 on theinterior of glove box 2 in order to protect gasket 10 from corrosion or,in the event of fire, from combustion of substances within glove box 2.Frame 20 is typically attached by welding to the inside of wall 4.

Another approach to a window assembly structure used in the prior artwith enclosures for containing hazardous substances involves bolting awindow directly to the exterior of the enclosures. FIG. 2 shows across-sectional view of such a window assembly mounted to the wall 22 ofan enclosure constructed as a hot cell. As with glove box 10, wall 22 isformed from plates of stainless steel. To prevent radiation fromescaping from the hot cell, the outside of wall 22 may be lined with alayer of lead 24 or a similar radiation-absorbing material. A window 26is provided that is also formed from radiation-absorbing materials, suchas with one or more sheets of glass and/or clear polycarbonatesimpregnated with lead. Depending on the radioactivity of the substancescontained within the hot cell enclosure, window 26 may have a thicknessof a few inches or more to prevent the escape of radiation. Window 26 ispositioned over the aperture in wall 22 and held in place by a flangedstainless steel frame 28 attached with bolts 30 welded directly to wall22. As seen in FIG. 2, a U-shaped gasket 32 of elastomeric materialsurrounds the edges of window 26 to seal the interfaces with wall 22 andframe 28.

While the above described window assembly designs have been usedextensively, they have inherent structural shortcomings that raiseconcerns in the construction and sealing of enclosures. The structure ofthe zipper type window assembly, for example, may encounter problemswhen sealing against high or low interior pressure conditions. Insituations where the pressure differential between the interior of theenclosure and the surrounding environment is substantial, failure of thegasket in a zipper window assembly has even led to windows being blownentirely out of their window apertures. The window assembly wherein awindow is bolted to the exterior of an enclosure also presents problems,especially when it is necessary to modify or replace a window. When anenclosure has been used to contain highly toxic or radioactivesubstances, material forming the enclosure walls may become contaminatedto the point that it may not be cut, drilled, ground, or otherwisereworked. Therefore, bolts welded to the enclosure walls that have beenstripped or damaged cannot be replaced. Likewise, if a thicker window isrequired to accommodate increased radiation levels within the enclosure,larger bolt holes may not be drilled in the walls to receive boltscapable of holding the higher window mass.

Another problem with these window assembly designs is that they providelittle or no reinforcement for the junction between a window and anenclosure wall. As previously described, enclosure walls are commonlyformed from plates of stainless steel. The thickness of this materialmay vary widely, with a ⅝ inch thick plate of stainless steel having atolerance of ±⅛ inch, for example. The plates of stainless steel mayalso be warped or twisted, especially for walls of large sizedenclosures. With the prior art window assemblies, such irregularitiesaround a window aperture may make it difficult to achieve proper sealingor may translate stress into the window itself. It has, therefore, beennecessary to planarize the plates of stainless steel around windowapertures by welding or grinding prior to attaching a window. Theseprocesses are time consuming and difficult to perform, and cannot becarried out on enclosure surfaces that have been contaminated by highlytoxic or radioactive substances.

In view of the foregoing, a need exists for improved window assembliesthat eliminate sealing problems and that simplify the installation,removal, and modification of enclosure windows.

BRIEF SUMMARY OF THE INVENTION

In accordance with the present invention, improved window assemblies aredisclosed for use with enclosures intended to hold substances that mustbe isolated or sealed from the surrounding environment. A windowassembly according to the present invention comprises a frame having areinforcing rim mounted to the wall of an enclosure surrounding anaperture formed therein. A window is seated on a ledge inside thereinforced rim with a U-shaped gasket surrounding the perimeter of thewindow, with the legs of the U-shape extending over either side of thewindow and the base of the U-shape covering the edge of the window. Anadditional frame portion is fastened onto the outside of the reinforcedrim to hold the window in place and seal the window assembly.

In a first embodiment of the present invention, the window assemblycomprises a two-piece window frame configured for welding to the wall ofthe enclosure surrounding the aperture. An inner frame member has aflange-shaped cross section with a lip that abuts against the enclosurewall surrounding the window aperture. The inner frame member is weldedto the enclosure wall, and a raised portion of the inner frame memberprojects outwardly to act as a reinforcing rim of the window assembly. Awindow surrounded by a U-shaped gasket is seated on a ledge runningaround the inside of the raised portion of the inner frame member. Anouter frame member is fastened over the outside of the window withfasteners such as by bolts or screws extending into the raised portionof the inner frame member. When tightened, the bolts compress the legsof the U-shaped gasket between the ledge of the inner frame member andthe outer frame member to form a seal.

In a second embodiment of the present invention, the window assemblycomprises a three-piece window frame configured for clamping to the wallof the enclosure surrounding the aperture. An inner frame member has alip carrying a sealing element that abuts against the inside of theenclosure wall surrounding the window aperture. The inner frame memberalso has an interior ledge onto which a window surrounded by a U-shapedgasket is seated. An intermediate frame member has a lip carrying asealing element that abuts against the outside of the enclosure wallsurrounding the window aperture. The inner and intermediate framemembers are bolted together to clamp them to opposite sides of theenclosure wall, with the intermediate frame member surrounding theperimeter of the window and acting as a reinforcing rim of the windowassembly. An outer frame member is fastened over the outside of thewindow with fasteners such as by bolts or screws passing through theintermediate frame member and into the inner frame member. As in thepreceding embodiment, tightening the bolts compresses the U-shapedgasket between the ledge on the inner frame member and the outer framemember to form a seal.

Other and further features and advantages of the present invention willbe apparent from the following descriptions of the various embodimentsread in conjunction with the accompanying drawings. It will beunderstood by one of ordinary skill in the art that the followingembodiments are provided for illustrative and exemplary purposes only,and that numerous combinations of the elements of the variousembodiments of the present invention are possible.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which illustrate what is currently considered to be thebest mode for carrying out the invention:

FIG. 1A is a perspective view of an exemplary glove box.

FIG. 1B is an enlarged sectional side view of a portion of a zipperwindow assembly taken along line X-X in FIG. 1A.

FIG. 2 is a sectional side view of a window assembly bolted directly tothe wall of an enclosure.

FIG. 3 is a perspective view of a wall of an enclosure.

FIGS. 4A and 4B show an inner frame member according to a firstembodiment of the present invention.

FIGS. 5A and 5B show an outer frame member according to the firstembodiment of the present invention.

FIG. 6 is a perspective view of the frame members in FIGS. 4A-5B boltedtogether.

FIGS. 7A and 7B show a completed window assembly according to the firstembodiment of the present invention.

FIGS. 8A and 8B show an inner frame member according to a secondembodiment of the present invention.

FIGS. 9A and 9B show an intermediate frame member according to thesecond embodiment of the present invention.

FIGS. 10A and 10B show an outer frame member according to the secondembodiment of the present invention.

FIG. 11 is a perspective view of the frame members in FIGS. 8A-10Bbolted together.

FIGS. 12A-12C show a completed window assembly according to the firstembodiment of the present invention.

FIG. 13 shows an alternative embodiment of a gasket with a keyholeshape.

DETAILED DESCRIPTION OF THE INVENTION

Referring in general to the accompanying drawings, various aspects ofthe present invention are illustrated to show exemplary windowassemblies as well as methods for their construction. Common elements ofthe illustrated embodiments are designated with like reference numeralsfor clarity. It should be understood that the figures presented are notmeant to be illustrative of actual views of any particular portion of awindow assembly or the structure of an enclosure to which such a windowassembly is attached, but are merely idealized schematic representationswhich are employed to more clearly and fully depict the invention.

As an example of a mounting location for a window assembly according tothe present invention, FIG. 3 shows a perspective view of a wall 34 thatforms the side of a sealed enclosure 36. Sealed enclosure 36 maycomprise any structure intended for isolating substances from theoutside environment such as a glove box or even a room-sized containerused for holding and processing large quantities of material. Wall 34may be formed from a plate of stainless steel; however, any othermaterials used conventionally for forming the walls of such sealedenclosures are also contemplated as being within the scope of thepresent invention. Examples of other materials include, but are notlimited to, other types of steel, aluminum, plastic, or compositematerials such as fiberglass. FIG. 3 shows that wall 34 includes anaperture 38 therethrough for receiving a window assembly to allowobservation of interior conditions within the sealed enclosure.

FIGS. 4A-7B illustrate a first embodiment of a window assembly accordingto the present invention comprising a two-piece window frame 100 (FIG.6). As seen in FIGS. 4A and 4B, the first piece of window frame 100comprises an inner frame member 102 that is configured to be welded intoaperture 38 of wall 34. FIG. 4B, which is an enlarged cross section ofinner frame member 102 taken along line A-A in FIG. 4A, shows that innerframe member 102 has a flange shape with a raised portion 104 and aledge 106 extending transversely thereto that runs around the insideperiphery of raised portion 104. Inner frame member 102 also includes alip 108 formed around the outside peripheral edge of raised portion 104.Lip 108 includes a first surface 110 configured to abut against theoutside of wall 34, and a second surface 112 configured to lie withinthe inside periphery of window aperture 38. Threaded bolt holes 114 areformed in, but not through, a mounting surface 116 of raised portion 44.FIG. 4B shows that in order to prevent the build-up of residualcontaminants on the interior surfaces of sealed enclosure 36, the insideperipheral edge of ledge 106 may be formed with a beveled surface 118.This reduces the possibility that substances will collect at theinterface of ledge 106 and the interior surface of a window, and furtherfacilitates cleaning. The outside edge of raised portion 104 may alsoinclude a beveled surface 120 to eliminate sharp comers on mountingsurface 116.

As shown in FIGS. 5A and 5B, the second piece of window frame 100comprises an outer frame member 122 that is configured to be fastenedover the outside of a window seated in inner frame member 102. Outerframe member 122 includes bolt holes 124 that are spaced for alignmentwith threaded bolt holes 114 in inner frame member 102. FIG. 5B, whichis an enlarged cross section of outer frame member 122 taken along lineB-B in FIG. 5A, shows that bolt holes 124 extend through outer framemember 122 from a top surface 126 to a clamping surface 128. Bolt holes124 may include countersink portions 130, such that the heads of boltsinserted therein may be flush with top surface 126. Outer frame member122 may also include beveled surfaces 132 and 134 to eliminate sharpcorners on top surface 126. FIG. 6 is a perspective view of window frame100, showing how outer frame member 122 is affixed to inner frame member102 with bolts 136.

FIG. 7A is a front, exterior view of a completed window assemblyaccording to the first embodiment of the present invention, whereinwindow frame 100 is mounted to enclosure wall 34 with a window 138covering aperture 38. FIG. 7B is an enlarged cross section of the windowassembly taken along line C-C in FIG. 7A. Inner frame member 102 issealed to wall 34 by welding along the interface between second surface112 of lip 108 and the inside of window aperture 38. For additionalstrength and sealing, inner frame member 102 may also be welded alongthe interface between first surface 110 of lip 108 and the outside ofwall 34. FIG. 7B shows the raised portion 104 of inner frame member 102projects outwardly from wall 34, while ledge 106 extends perpendicularlyacross aperture 38. A U-shaped gasket 140 of an elastomeric material isplaced around the periphery of window 138. The legs of U-shaped gasket140 overlap peripheral inner and outer portions of window 138 and mayinclude one or more ridges 142 for providing sealing beads to becompressed between the inner and outer frame members 102, 122 and window138. Window 138 is seated on ledge 106 around the inside of raisedportion 104 and outer frame member 122 is fastened to mounting surface116 of inner frame member 102 with bolts 136 driven into threaded boltholes 114. The clamping surface 128 of outer frame member 122 is thuscompresses down on the legs of U-shaped gasket 140 with window 138disposed therebetween, to form a leak-tight seal around window 138. Asshown in FIG. 7B, the base of U-shaped gasket 140 is slightly spacedfrom the inner wall of raised portion 104 of inner frame member 102 toaccommodate temperature fluctuations and expansion of materials.

According to the foregoing description, the first embodiment of thepresent invention provides a window assembly that overcomes the problemsassociated with previous window assembly designs for sealed enclosures.Securing window 138 between ledge 106 of inner frame member 102 andclamping surface 128 of outer frame member 122 eliminates thepossibility that a pressure differential will cause window 138 to beblown out due to a gasket failure. Forming inner frame member 102 withraised portion 104 also provides window frame 100 with a substantiallyplanar reinforcing rim having a uniform thickness. This eliminates thedifficulty with sealing window 138 directly against surfaces of wall 34,which may exhibit warping, twisting, or variations in thickness, andreduces stress concentrations that may otherwise be induced in window138. Furthermore, because threaded bolt holes 114 are formed in raisedportion 104, they are spaced outwardly from the interior of sealedenclosure 36 and may be repaired or modified without having to reworkcontaminated wall materials.

FIGS. 8A-13 illustrate a second embodiment of a window assemblyaccording to the present invention comprising a three-piece window frame200 (FIG. 11). As seen in FIGS. 8A and 8B, the first piece of windowframe 200 comprises an inner frame member 202 that is configured to beattached to the inside of wall 34 around aperture 38. FIG. 8B, which isan enlarged cross section of inner frame member 202 taken along line D-Din FIG. 8A, shows that inner frame member 202 has an outer peripherallip 204 for abutting against the inside of wall 34 around aperture 38.Lip 204 includes a channel 206 for receiving a sealing element (notshown) to seal the interface between lip 204 and the inside of wall 34.Inner frame member 202 also has a raised portion 208 and a ledge 210that runs around the inside periphery of raised portion 208. Threadedbolt holes 212 are formed in a mounting surface 214 of raised portion208. FIG. 8B shows that inner frame member 202 may also include beveledsurfaces 216 and 218 in order to prevent the build-up of residualcontaminants on the interior surfaces of sealed enclosure 36.

As shown in FIGS. 9A and 9B, the second piece of window frame 200comprises an intermediate frame member 220 that is configured to beattached to the outside of wall 34 around aperture 38. Intermediateframe member 220 includes bolt holes 222 that are spaced for alignmentwith threaded bolt holes 212 in inner frame member 202. FIG. 9B, whichis an enlarged cross section of intermediate frame member 220 takenalong line E-E in FIG. 9A, shows that bolt holes 222 extend throughintermediate frame member 220 from a mounting surface 224 to a clampingsurface 226 for abutting against the outside of wall 34 around aperture38. Bolt holes 222 may include countersink portions 228, such that theheads of bolts inserted therein may be flush with mounting surface 224.As seen in FIG. 9A, only every other bolt hole 222 is provided with acountersink portion 228. This is because the remaining bolt holes 222are intended to receive bolts which also pass through an outer framemember 232 (FIGS. 10A and 10B). The clamping surface 226 of intermediateframe member 220 includes a channel 230 for receiving a sealing element(not shown) to seal the interface between clamping surface 226 and theoutside of wall 34.

FIGS. 10A and 10B show that the third piece of window frame 200comprises an outer frame member 232 that is configured to be fastenedover the outside of a window seated in inner frame member 202 andintermediate frame member 220. Outer frame member 232 includes boltholes 234 that are spaced for alignment with threaded bolt holes 212 ininner frame member 202. FIG. 10B, which is an enlarged cross section ofouter frame member 232 taken along line F-F in FIG. 10A, shows that boltholes 234 extend through outer frame member 232 from a top surface 236to a clamping surface 238. Bolt holes 234 may include countersinkportions 240, such that the heads of bolts inserted therein may be flushwith top surface 236. Outer frame member 232 may also include beveledsurfaces 242 and 244 to eliminate sharp corners on top surface 236. FIG.11 is a perspective view of window frame 200, showing how outer framemember 232, intermediate frame member 220, and inner frame member 202are held together with bolts 246.

FIG. 12A is a front, exterior view of a completed window assemblyaccording to the second embodiment of the present invention, whereinwindow frame 200 is mounted to enclosure wall 34 with a window 248covering aperture 38. FIG. 12B is an enlarged cross section of thewindow assembly taken along line G-G in FIG. 12A, and FIG. 12C is anenlarged cross section of the window assembly taken along line H-H inFIG. 12A. Inner frame member 202 is placed within the interior of sealedenclosure 36 with lip 204 abutting against the inside of wall 34 aroundaperture 38. A sealing element 250 of, for example, elastomeric materialis seated in channel 206 of lip 204 to seal the interface between lip204 and the inside of wall 34. FIGS. 12B and 12C show that raisedportion 208 of inner frame member 202 projects outwardly into aperture38, while ledge 210 extends perpendicularly thereto across aperture 38.Intermediate frame member 220 is placed on the exterior of sealedenclosure 36 with clamping surface 226 abutting against the outside ofwall 34 around aperture 38. Another sealing element 252 is seated inchannel 230 of clamping surface 204 to seal the interface betweenclamping surface 204 and the outside of wall 34. While sealing elements250 and 252 are depicted as O-ring type gaskets, other sealing elementshapes may be used. For example, FIG. 13 shows a sealing element 250′having a keyhole shaped cross section held in place by a channel 206′having inwardly canted sides. This arrangement reduces the chance thatgasket 250′ may become unseated from channel 206′ and providesadditional sealing surfaces. Returning to FIG. 12C, inner frame member202 and intermediate frame member 220 are bolted together with wall 34clamped therebetween and bolts 246 a driven into threaded bolt holes212. Bolts 246 a are only inserted into bolt holes 222 havingcountersink portions 228, such that the heads of bolts 246 a are flushwith mounting surface 224, and the remainder of bolt holes 222 remainfree to receive bolts 246 b that pass through outer frame member 232.

A U-shaped gasket 254 of an elastomeric material is placed around theperiphery of window 248. The legs of U-shaped gasket 254 overlapperipheral inner and outer portions of window 248 and may include one ormore ridges 256 for providing additional sealing beads to be compressedbetween inner and outer frame members 202, 232. Window 248 is seated onledge 210 around the inside periphery of raised portion 208 withintermediate frame member 220 surrounding the perimeter of window 248.Outer frame member 232 is fastened to mounting surface 224 ofintermediate frame member 220 with bolts 246 b driven into threaded boltholes 212. Thus, the clamping surface 238 of outer frame member 232 andledge 210 of inner frame member 202 press down on the legs of U-shapedgasket 254 with window 248 therebetween, to form a leak-tight sealaround window 248.

As with the first embodiment of the present invention, the secondembodiment of the present invention provides a window assembly thatovercomes the problems associated with previous window assembly designsfor sealed enclosures. Securing window 248 between ledge 210 of innerframe member 202 and clamping surface 238 of outer frame member 232eliminates the possibility that a pressure differential will causewindow 248 to be blown out due to a gasket failure. Intermediate framemember 220 also provides window frame 200 with a substantially planarreinforcing rim having a uniform thickness. As previously discussed,this eliminates the difficulty with sealing window 248 directly againstsurfaces of wall 34, and reduces stress concentrations that may damagewindow 248. Furthermore, because window frame 200 is clamped to thesurfaces of wall 34, it may be installed and removed without having torework contaminated wall materials. In situations where an enclosure hasreached the end of its product life or must be decommissioned, thisclamped arrangement also enables window frame 200 to be salvaged for usein another enclosure. The three piece construction of window frame 200also enables it to be easily modified. For example, if a differentwindow thickness is required to accommodate radiation levels within ahot cell type enclosure, intermediate frame member 220 may be replacedwith an intermediate frame member of a different thickness.

To fabricate the window assemblies of the first and second embodimentsof the present invention, frame members 102, 122, 202, 220, and 232 maybe formed, for example, of stainless steel by machining or with a highdensity casting process. This provides highly planar frame members ofuniform thickness that exhibit the corrosion resistance and ease ofcleaning previously described above. The frame members may also beformed of other materials, including but not limited to, other types ofsteel or aluminum, plastic, or composite materials such as fiberglass.Of course, the types of materials that may be used for forming the framemembers will depend in part on the substances and environmentalconditions within a sealed enclosure to which they are attached, and, atleast in the case of the first embodiment, whether or not they may bewelded. Gaskets 140, and 254, and sealing elements 250 and 252 may beformed of any resilient material that has suitable sealing propertiesand is resistant to deterioration by the surrounding environmentalconditions. An example of a commonly used gasket and sealing material isEPDM (ethylene propylene diene monomer).

While the above embodiments have been described in terms of mountingwindows to the walls of sealed enclosures, it is also within the scopeof the present invention to use frames 100 and 200 for mounting andsealing other structures to a wall. For example, frames 100 and 200could be mounted around an access portal intended for inserting orremoving substances or to provide a service panel, and windows 138 and248 could be replaced with a plate of material such as stainless steelto cover and seal the access portal when not in use. Suitably configuredframes 100 and 200 could also be used to mount and seal ducts or pipesto access portals intended for passing power, gas, vacuum, or otherutilities into the interior of an enclosure. A flanged rim at the endof, or disposed about the exterior of the duct or pipe would simply becovered by a U-shaped gasket and secured between the frame members offrames 100 and 200 in the same manner as the edges of windows 138 and248.

Each of the above-illustrated embodiments and variations thereof of thepresent invention provides improved mounting and sealing of windows orother structures to the walls of enclosures intended to hold substancesthat must be isolated or sealed from the surrounding environment.Although the present invention has been depicted and described withrespect to the illustrated embodiments, various additions, deletions andmodifications are contemplated within its scope. For example, whileframes 100 and 200 have been illustrated as being configured withperimeter outlines for mounting to a generally square aperture 38,frames 100 and 200 could be also be formed with perimeter outlines formounting to apertures having circular, oval, or any other shape.Furthermore, while the lip surfaces, ledge surfaces, and clampingsurfaces of the various frame members have been depicted as beingconfigured for interfacing with planar wall and window surfaces, othersurface contours are possible. With hot cell type enclosures, forexample, the lip, ledge and clamping surfaces may have a stepped contourfrom outer to inner periphery in order to interface with similarlystepped window and wall surfaces formed to prevent radiation leakagethrough seams. The scope of the invention is, therefore, indicated bythe appended claims rather than the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims areto be embraced within their scope.

1. A frame assembly configured for attachment to a wall surrounding anaperture therethrough, comprising: a first frame member having a ledgesurrounding a central opening in the first frame member and a raisedportion extending perpendicular to and surrounding the ledge; a lipformed in the first frame member around an outer edge of the raisedportion, the lip having a first surface adapted to abut against anoutside surface of a wall and a second surface adapted to lie within aninside periphery of an aperture passing through the wall; a plurality ofthreaded holes formed in a mounting surface on the raised portion of thefirst frame member; a second frame member having a clamping surfacesurrounding a central opening in the second frame member, wherein theclamping surface is adapted to abut against the mounting surface of thefirst frame member and overlie the ledge of the first frame member; anda plurality of holes extending through the second frame member, whereinthe plurality of holes is spaced for alignment with the plurality ofthreaded holes in the first frame member and the second frame member isfastened to the mounting surface of the first frame member with aplurality of threaded fasteners.
 2. The frame assembly of claim 1,wherein the first frame member is welded to a wall of the sealedenclosure along an interface between the second surface of the lip inthe first frame member and an inside periphery of an aperture passingthrough the wall, and further comprising: a plate having peripheralinner and outer portions surrounded by legs of a U-shaped gasketdisposed about the plate, wherein the plate is seated on the ledge ofthe first frame member, and wherein the clamping surface of the secondframe member compresses the legs of the U-shaped gasket between thefirst and second frame members.
 3. The frame assembly of claim 2,wherein the sealed enclosure comprises a glove box or a hot cell.
 4. Theframe assembly of claim 2, wherein the plate comprises a window.
 5. Theframe assembly of claim 4, wherein the window is impregnated with aradiation-absorbing material.
 6. The frame assembly of claim 2, whereinthe plate comprises one of steel, plastic, or a resin-based compositematerial.
 7. The frame assembly of claim 2, wherein the plate comprisesa flanged rim of a duct or pipe.
 8. The frame assembly of claim 1,wherein the first frame member and the second frame member comprise astainless steel.
 9. A frame assembly configured for attachment to a wallsurrounding an aperture therethrough, comprising: a first frame memberhaving a ledge surrounding a central opening in the first frame memberand a raised portion extending perpendicular to and surrounding theledge; a lip formed in the first frame member around an outer peripheraledge of the raised portion, the lip having a first surface adapted toabut against an inside surface of a wall and a second surface adapted tolie within an inside periphery of an aperture passing through the wall;a plurality of threaded holes formed in a mounting surface on the raisedportion of the first frame member; a second frame member having amounting surface and an opposing clamping surface surrounding a centralopening in the second frame member, wherein the clamping surface of thesecond frame member is adapted to abut against an outside surface of thewall; a plurality of holes extending through the second frame member,wherein the plurality of holes extending through the second frame memberis spaced for alignment with the plurality of threaded holes in thefirst frame member; a third frame member having a clamping surfacesurrounding a central opening in the third frame member, wherein theclamping surface of the third frame member is adapted to abut againstthe mounting surface of the second frame member and overlie the ledge ofthe first frame member; and a plurality of holes extending through thethird frame member, wherein the plurality of holes extending through thethird frame member is spaced for alignment with the plurality ofthreaded holes in the first frame member and the second and third framemembers are fastened to the first frame member with a plurality ofthreaded fasteners.
 10. The frame assembly of claim 9, wherein the lipof the first frame member is clamped to an inside surface of a wall of asealed enclosure and the clamping surface of the second frame member isclamped to an outside surface of the wall of the sealed enclosure withthe plurality of threaded fasteners, and further comprising: a platehaving peripheral inner and outer portions surrounded by legs of aU-shaped gasket disposed about the plate, wherein the plate is seated onthe ledge of the first frame member, and wherein the clamping surface ofthe third frame member is fastened to the mounting surface of the secondframe member with the plurality of threaded fasteners and compresses thelegs of the U-shaped gasket between the first and second frame members.11. The frame assembly of claim 10, wherein the sealed enclosurecomprises a glove box or a hot cell.
 12. The frame assembly of claim 10,wherein the plate comprises a window.
 13. The frame assembly of claim12, wherein the window is impregnated with a radiation-absorbingmaterial.
 14. The frame assembly of claim 10, wherein the platecomprises one of steel, plastic, or a resin-based composite material.15. The frame assembly of claim 10, wherein the plate comprises aflanged rim of a duct or pipe.
 16. The frame assembly of claim 10,wherein the plurality of threaded fasteners comprises a first pluralityof threaded fasteners and a second plurality of threaded fasteners,wherein the first plurality of threaded fasteners underlies the thirdframe member and fastens the second frame member to the first framemember, and wherein the second plurality of threaded fasteners fastensthe third frame member to the first and second frame members.
 17. Theframe assembly of claim 9, wherein the first frame member, the secondframe member, and the third frame member each comprise a stainlesssteel.
 18. The frame assembly of claim 9, wherein at least one of thelip of the first frame member and the clamping surface of the secondframe member includes a sealing element adapted to seal against asurface of an enclosure wall.
 19. The frame assembly of claim 18,wherein the sealing element has a keyhole-shaped cross section and isseated in a channel formed in the lip of the first frame member or theclamping surface of the second frame member.
 20. A kit for a frameassembly configured for attachment to a wall surrounding an aperturetherethrough, comprising: a first frame member having a ledgesurrounding a central opening in the first frame member and a raisedportion extending perpendicular to and surrounding the ledge; a lipformed in the first frame member around an outer edge of the raisedportion, the lip having a first surface adapted to abut against anoutside surface of a wall and a second surface adapted to lie within aninside periphery of an aperture passing through the wall; a plurality offastener-receiving holes formed in a mounting surface on the raisedportion of the first frame member; a second frame member having aclamping surface surrounding a central opening in the second framemember, wherein the clamping surface is adapted to abut against themounting surface on the raised portion of the first frame member andoverlie the ledge of the first frame member; and a plurality of holesextending through the second frame member, wherein the plurality ofholes is spaced for alignment with the plurality of fastener-receivingholes in the first frame member.
 21. A kit for a frame assemblyconfigured for attachment to a wall surrounding an aperturetherethrough, comprising: a first frame member having a ledgesurrounding a central opening in the first frame member and a raisedportion extending perpendicular to and surrounding the ledge; a lipformed in the first frame member around an outer edge of the raisedportion, the lip having a first surface adapted to abut against aninside surface of a wall and a second surface adapted to lie within aninside periphery of an aperture passing through the wall; a plurality offastener-receiving holes formed in a mounting surface on the raisedportion of the first frame member; a second frame member having amounting surface and an opposing clamping surface surrounding a centralopening in the second frame member, wherein the clamping surface of thesecond frame member is adapted to abut against an outside surface of thewall; a plurality of holes extending through the second frame member,wherein the plurality of holes extending through the second frame memberis spaced for alignment with the plurality of fastener-receiving holesin the first frame member; a third frame member having a clampingsurface surrounding a central opening in the third frame member, whereinthe clamping surface of the third frame member is adapted to abutagainst the mounting surface of the second frame member and overlie theledge of the first frame member; and a plurality of holes extendingthrough the third frame member, wherein the plurality of holes extendingthrough the third frame member is spaced for alignment with theplurality of fastener-receiving holes in the first frame member.